Discourse: >> Discourse >> 0.9.8.5 Security Vulnerabilities
Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, fail-open access control in Data Explorer plugin allows any authenticated user to execute SQL queries that have no explicit group assignments, including built-in system queries. Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. As a workaround, either explicitly set group permissions on each Data Explorer query that doesn't have permissions, or disable discourse-data-explorer plugin.
CVSS Score
5.4
EPSS Score
0.0
Published
2026-02-26
Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, an improper authorization check in the topic management logic allows authenticated users to modify privileged attributes of their topics. By manipulating specific parameters in a PUT or POST request, a regular user can elevate a topic’s status to a site-wide notice or banner, bypassing intended administrative restrictions. Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. There are no practical workarounds to prevent this behavior other than applying the security patch. Administrators concerned about unauthorized promotions should audit recent changes to site banners and global notices until the fix is deployed.
CVSS Score
4.3
EPSS Score
0.001
Published
2026-02-26
Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, TL4 users can publish topics into staff-only categories via the `publish_to_category` topic timer, bypassing authorization checks. Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known workarounds are available.
CVSS Score
2.7
EPSS Score
0.0
Published
2026-02-26
Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, moderators could export user Chat DMs via the CSV export endpoint by exploiting an overly permissive allowlist in `can_export_entity?`. The method allowed moderators to export any entity not explicitly blocked instead of restricting to an explicit allowlist. Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known workarounds are available.
CVSS Score
2.7
EPSS Score
0.0
Published
2026-02-26
Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, a user full name can be evaluated as raw HTML when the following settings are set: `display_name_on_posts` => true; and `prioritize_username_in_ux` => false. Editing a post of a malicious user would trigger an XSS. Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known workarounds are available.
CVSS Score
6.1
EPSS Score
0.0
Published
2026-02-26
Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, SQL injection in PM tag filtering (`list_private_messages_tag`) allows bypassing tag filter conditions, potentially disclosing unauthorized private message metadata. Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known workarounds are available.
CVSS Score
6.5
EPSS Score
0.0
Published
2026-02-26
Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, missing `validate_before_create` authorization in Data Explorer's `QueryGroupBookmarkable` allows any logged-in user to create bookmarks for query groups they don't have access to, enabling metadata disclosure via bookmark reminder notifications. Versions 2025.12.2, 2026.1.1, and 2026.2.0 fix this issue and also make sure `validate_before_create` throws NotImplementedError in BaseBookmarkable if not implemented, to prevent similar issues in the future. No known workarounds are available.
CVSS Score
3.8
EPSS Score
0.0
Published
2026-02-26
Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, the `move_posts` action only checked `can_move_posts?` on the source topic but never validated write permissions on the destination topic. This allowed TL4 users and category group moderators to move posts into topics in categories where they lack posting privileges (e.g., read-only categories or categories with group-restricted write access). Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known workarounds are available.
CVSS Score
2.7
EPSS Score
0.0
Published
2026-02-26
Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, DM communication-preference bypass when adding members via `Chat::AddUsersToChannel` — a user could add targets who have blocked/ignored/muted them to an existing DM channel, bypassing per-recipient PM restrictions that are enforced during DM channel creation. Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known workarounds are available.
CVSS Score
3.8
EPSS Score
0.0
Published
2026-02-26
Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, `posts_nearby` was checking topic access but then returning all posts regardless of type, including whispers that should only be visible to whisperers. Use `Post.secured(guardian)` to properly filter post types based on user permissions. Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known workarounds are available.
CVSS Score
4.9
EPSS Score
0.0
Published
2026-02-26
Page 1